Doped semiconductors have for some time been used as photodetectors. Incident photons of light supply the energy to raise charge carriers (electrons or holes) of doping impurities from the ground state to a conducting state, resulting in a detectable electric current the magnitude of which indicates the intensity of light. There currently exists great interest in developing photodetectors, most especially semiconductor photodetectors, effective for the far infrared and millimeter wave regions of the electromagnetic spectrum. In the past, heterostructures have been used for this purpose, an example of which is given in Statutory Inventorship Registration No. H95 to Shanabrook et al., the disclosure of which incorporated herein by reference. The Shananbrook et al. document discloses a heterostructure in which charge carriers migrate, as in any heterostructure, from barrier to adjacent well layers, where the carriers become weakly bound to doping impurities in the well layers. These weak bonds, allow light photons of corresponding low energies to raise these charge carriers to the conduction band, where they contribute to detection of current. Unfortunately, even though these weak binding energies permit detection of very low light frequencies, the frequency range does not extend far enough to meet current needs. Moreover, permitted quantum states in such devices are determined by the dimensions of such devices, which are set at the time of device fabrication, and thus the frequencies of light for which these devices detect, are also set at fabrication. Permitting the tuning of such devices to desired light frequencies would be most welcome in the art.